The present invention relates generally to motorized convertible seat-bed assemblies. More particularly, this invention relates to such assemblies mounted in motor vehicles.
A number of prior seat-bed assemblies are known which are manually convertible from a seating position to a bed position. One example of such a seat-bed assembly suitable for vehicular mounting is shown in U.S. Pat. No. 4,321,716 issued to Shrock. However, especially in campers and vans, it has been found to be desirable to provide a seat-bed assembly having automatic position conversion and, at the same time, simplify the conversion mechanism.
Prior motorized devices for seat-bed conversion are known. One example of such a device is shown in U.S. Pat. No. 4,321,716, issued to Shrock et al. However, these motorized devices have not always performed satisfactorily. For example, drive motors have been located between the seat frame and the inner wall of the vehicle in order to optimize storage space under the seat. Unfortunately, such dispositions can make repair and replacement of the drive motor elements more difficult. Likewise it is difficult to retrofit a manual conversion assembly to a motorized unit with such arrangements.
Also, some pivotal linkages and multi-track guides for the seat member can cause the front of the seat to rise significantly during conversion. In such cases it may be difficult or impossible for the seat-bed to be occupied during conversion. At the same time, the cushion elements of some assemblies are undesirably compressed or worn by such vertical motion.
Further, some prior linkage arrangements are susceptable to binding during conversion, especially when the seat-bed is occupied. In addition, it has been found to be desirable to improve the load-bearing capacity and relative stability of the seat and back members especially in the bed position.
Accordingly, it is an object of this invention to provide an improved seat-bed assembly.
Another object is to provide a seat-bed assembly having increased leverage in the conversion mechanism so as to decrease the necessary drive motor force.
A further object is to provide improved stability and occupant support in seat-bed assemblies at minimal expense.
Yet another object is to provide a seat-bed conversion device which applies reduced strain on cushion components of the seat and back members.
Still another object is to provide a drive motor device for seat bed assemblies which is readily accessible for servicing.
Yet still another object is to provide a drive motor device which can be retrofit into seat-bed assemblies already installed in motor vehicles.
Still a further object is to provide a reliable seat-bed assembly which can be adjusted into a plurality of intermediate positions even when occupied.
These and other objects of the present invention are attained by the provision of a seat-bed assembly having a conversion linkage fixedly attached to the seat member and disposed so as to restrict movement of the seat member during conversion. The seat member is slidable along a path determined by a guide track and avoids excess vertical motion. The conversion driver is mounted to the supporting frame and connects directly to the conversion linkage. The fixed connection of the conversion linkage to the seat member occurs at a rearward extension of the seat member. The back member includes a support projection on its rear surface which rests on that rearward extension to provide increased stability to the back member in the bed position.
In particular, the seat-bed assembly includes a seat member, a back member, side frame members and a conversion linkage on each side which is fixed to the seat member, pivotally mounted to the back member and slidably mounted to the side frame member. A threaded drive rod and drive nut device are mounted to the linkage at the fixed connection to the seat member. The drive rod is selectively rotated by a worm gear mounted on the side frame member. The worm gears on each side are connected to a central drive motor by speedometer-type cables. The central drive motor is located on a bridging element joining each side frame member under the seat member.
The conversion linkage fixed to the seat member includes two spaced apart links. Rollers are mounted on the free ends of these links and disposed within a single roller guide track on the side frame member. The guide track is disposed in the direction of desired seat member motion during conversion. The conversion linkage connects to the back member through a pivotable joint with at least one of the links at the guide track roller.
Other objects, advantages and novel features of the present invention will now become readily apparent upon consideration of the following descriptions of preferred embodiments in conjunction with the drawings.